I have a HP with a 2.5 GHz Processor 2 gig ram running XP media center SP 3, and when it rebooted yesterday I got the message Windows could not start because the following file is missing or corrupt <windows root>\system32\NTOSKRNL.EXE.
I was able to boot up using a different keyboard and mouse once, so I did a system restore from a week ago that didn't help.
I am using a PS2 connect keyboard, so I switched to a usb connect keyboard. That worked the first time, so I rebooted with it plugged in and I got the same message. I tried a different mouse, but that didn't work. After that I unplugged everything except the monitor and it booted up then I plugged the keyboard and mouse into the usb ports and everything worked. I rebooted with everything plugged in and I get the message. I thought I would try to repair the ntoskrnl.exe, so I have a xp pro CD and put it in CD drive, but when it starts and ask to boot from CD I hit enter and shortly afterwards I get the message again. If boot without keyboard I can't press enter.